When a Player is kicked from a server after just joining (example a banned player) the Player List will bug out, and the Player’s name will not be removed from the Player List Gui.
Reproduce Place: Player List bug - Roblox
Repro Steps:
- Join the Server on one account
- Join the server from a Different Computer/Account
- The game will kick any player who joins the game if there is already a player in game.
- Kicked Players name will not be removed from the Gui.
Also I wasn’t able to reproduce it, but some times when this glitch happens the player being kicked will gain the ROBLOX Admin Icon by there name, although every time I have seen this the player was not in the server anywhere.
Also I reproduced it today, when a Player who got temporary banned from one of my servers (for leaving the server while he was serving his Penalty Minute) and then the player attempted to rejoin the server and was kicked by the ban script. His name was not removed from the Board and he had a Admin Icon next to his name. Forgot to take a Screen shot of it 
And yes manbutt4 is not a ROBLOX Admin, I checked 